Candida albicans expresses a focal adhesion kinase-like protein that undergoes increased tyrosine phosphorylation upon yeast cell adhesion to vitronectin and the EA.hy 926 human endothelial cell line

Infect Immun. 2002 Jul;70(7):3804-15. doi: 10.1128/IAI.70.7.3804-3815.2002.

Abstract

The signaling pathways triggered by adherence of Candida albicans to the host cells or extracellular matrix are poorly understood. We provide here evidence in C. albicans yeasts of a p105 focal adhesion kinase (Fak)-like protein (that we termed CaFak), antigenically related to the vertebrate p125Fak, and its involvement in integrin-like-mediated fungus adhesion to vitronectin (VN) and EA.hy 926 human endothelial cell line. Biochemical analysis with different anti-chicken Fak antibodies identified CaFak as a 105-kDa protein and immunofluorescence and cytofluorimetric analysis on permeabilized cells specifically stain C. albicans yeasts; moreover, confocal microscopy evidences CaFak as a cytosolic protein that colocalizes on the membrane with the integrin-like VN receptors upon yeast adhesion to VN. The protein tyrosine kinase (PTK) inhibitors genistein and herbimycin A strongly inhibited C. albicans yeast adhesion to VN and EA.hy 926 endothelial cells. Moreover, engagement of alpha v beta 3 and alpha v beta 5 integrin-like on C. albicans either by specific monoclonal antibodies or upon adhesion to VN or EA.hy 926 endothelial cells stimulates CaFak tyrosine phosphorylation that is blocked by PTK inhibitor. A role for CaFak in C. albicans yeast adhesion was also supported by the failure of VN to stimulate its tyrosine phosphorylation in a C. albicans mutant showing normal levels of CaFak and VNR-like integrins but displaying reduced adhesiveness to VN and EA.hy 926 endothelial cells. Our results suggest that C. albicans Fak-like protein is involved in the control of yeast cell adhesion to VN and endothelial cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antigens, Bacterial / biosynthesis
  • Antigens, CD / metabolism
  • Candida albicans / enzymology*
  • Candida albicans / genetics
  • Candida albicans / metabolism
  • Cell Adhesion
  • Cell Line
  • Endothelium, Vascular / cytology
  • Enzyme Activation
  • Focal Adhesion Kinase 1
  • Focal Adhesion Protein-Tyrosine Kinases
  • Humans
  • Integrin alphaV
  • Integrin beta Chains*
  • Integrin beta3
  • Integrins / metabolism
  • Mutagenesis
  • Phosphorylation
  • Platelet Membrane Glycoproteins / metabolism
  • Protein-Tyrosine Kinases / metabolism*
  • Receptors, Vitronectin / metabolism
  • Tyrosine / metabolism*
  • Vitronectin / metabolism*

Substances

  • Antigens, Bacterial
  • Antigens, CD
  • Integrin alphaV
  • Integrin beta Chains
  • Integrin beta3
  • Integrins
  • Platelet Membrane Glycoproteins
  • Receptors, Vitronectin
  • Vitronectin
  • integrin alphaVbeta5
  • integrin beta5
  • Tyrosine
  • Protein-Tyrosine Kinases
  • Focal Adhesion Kinase 1
  • Focal Adhesion Protein-Tyrosine Kinases
  • PTK2 protein, human